Sparking plug for internal-combustion engines



1th. 29 1924. I 1,482,345

' A. G. BROWN SPARKING PLUG FOR INTERNAL COMBUSTIONENGINES Filed Nov. '29 1920 W I U j/ wz/v'fok Patented Jan. 29, 1924.

UNITED". STATES PATENT OFF-ICE.

ALBERT GEORGE BROWN, 0]? LONDON, ENGLAND. ASSIGNOR TO THE BROWN PISTOL SPARRING PLUG LIMITED, 01? LONDON, ENGLAND, A BRITISH COMPANY.

SPARRING PLUG FOR INTERNAL-COMBUSTION ENGINES.

Application filed November 29, 1920.

To (ZZZ 10 7mm it may concern Be it known that I, ALBERT GEORGE' Bnowx. a subject of the King of Great Britain. residing at 11 Clonmore Street;

Southfields, London, S. V. 18, England, have invented new and useful Improvements in Sparking Plugs for Internal-Combustion Engines, of which the following is a specifieation.

This invention is particularly intended for use on motor cars and cycles and has for its object to provide a sparking plug which shall be continually cooled in order to produce more efficient sparking and combustion of the explosive mixture and so enable greater efficiency to be maintained in the engine and avoid the many objections consequent upon the plugs becoming sooted.

The invention accordingly consists in a sparking plug of the kind adapted to be situated outside instead of inside the normal contour of the cylinder casing, essentially characterized in that one of the electrodes is hollow and has a straight-through passage which can be freely swept by a current of air so as to keep it efficiently cool. In the accompanying drawing, Fig. 1 rep resents a cross-section of an improved sparking plug constructed according to one manner of carrying the invention into effeet; Fig. 2 is a side elevation of the plug casing viewed from the side of Fig. 1, and Figs. and 4 are enlarged views of hollow electrodes.

The plug casing comprises a tubular body 1 mounted in the cylinder by means of a screwed end 2, so as to remain wholly or mainly outside the normal contour of the cylinder casing.

The top of the tubular passage 3 is traversed by a transverse passage 4, Fig. 2, and surmounted by an inspection opening closed by a screw cap 6. Earthed electrodes 7, Fig. 2, of which two are illustrated, are adjustably mounted by screw threads in the walls of the passage 4. The hollow electrode 8 is mounted within and along the passage 4 and consists essentially in a hollow open-ended tube provided with insulating blocks 9, 9*, one of which is fixed and the other removable, the blocks being of suitable size to fit the shouldered ends 10. 10, of the passage 4, and serving as a mounting for the electrode. The electrode is set up in position by placing the fixed Serial No. 427,258.

insulating block 9 in its recess 10 so that the electrode passes through the passage. The detachable insulating block 9 is placed over the free end of the electrode so as to engage in its recess 10*, the parts being then held together and in place by screwing up the detached nut 11.

The insulating blocks may be constructed of any suitable material. In Fig. 3 I have illustrated a manner of constructing the electrode with mica-blocks and in Fig. 4 with porcelain blocks.

According to Fig. 3 the hollow electrode is fitted at one end with a fixed sleeve 12 having a flange 12' at its inner end, the mica insulator 13 being mounted on the sleeve and a copper-asbestos washer 14* being set up on the electrode and locked by a nut 14 to ensure gastightness. The detachable block 13 is mounted on a second flanged sleeve 12 which forms a sliding fit with the electrode and is placed in position after the electrode has been passed through the passage 4, the assemblage being retained in place by the nut 15 screwed to the electrode with the interposition of a second gas tight washer 15.

According to Fig. 4, the porcelain blocks are cupped as shown at 16 to receive a boss 17 formed on the electrode, washers 18, 18 being inserted between the bearing surfaces. In both cases washers are preferably pro vided between. the engaging surfaces of the blocks and the shoulders of the passage 1' to ensure gastightness.

As the tubular electrode is not suitable to receive the ordinary ring-shaped terminal of. the magneto wires, I provide a special terminal consisting of two spring tongues 19, Fig. 1, one of which has a spherical projection 20, a circular hole 21 preferably being made in the other (which is shown partly in section) to receive the projection when not in use. The usual ring-shaped terminal of the magneto wire is inserted between the tongues so that the spherical proj ection engages with the central hole. I find in practice that this constitutes a perfectly dependable connection which does not become shaken ofi' nor accidentally drawn apart, and that the bearing surfaces are adequate to provide an unimpaired spark.

In use, the sparking plug is set up so that the passage through the electrode lies in the direction of motion of the car, so that a current of air is continually driven through the electrode by the motion of the car, and/or the radiator fan. Further, as the electrode is situated well clear of the cylinder casing, further advantages in cooling are secured from the general construction.

It will be seen that the sparking plug is simple in construction and. easy to take down when desired. The inspection opening serves the double purpose of allowing the insertion of the usual standard gap-setting device provided on a common form of magneto spanner for the adjustment oi the points 7, and of allowing petrol to be primed into the cylinder before starting up, in accordance with a common practice. The adjusting nuts are made of standard size so that the usual magnetic spanner sul'lices to tighten them up. Preferably the electrode securing nuts have the external edges of the threaded passage bevelled off to heighten and along the transverse passage so that part of its outer wall treely accessible to the motive gases and its inner wall is adapted to be swept by a current of air passing straight through the electrode, and earthed electrodes adjustably mounted in proximity to the exterior of the insulated electrode.

ALBERT GEORGE BROVVX. 

